System and method for manufacturing a thermal battery

ABSTRACT

An automated system and method for manufacturing a thermal battery is disclosed. In an exemplary embodiment, the system comprises a press system, a stacking system, and an enclosing system to automate the manufacturing process of thermal batteries. A method of manufacturing a thermal battery using the system is also disclosed. An automated tracking, storage, and retrieval system for pellets used in the manufacturing process and a pellet pairing system are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S. Ser.No. 11/670,856 entitled “SYSTEM AND METHOD FOR MANUFACTURING A THERMALBATTERY” filed Feb. 2, 2007 now U.S. Pat. No. 7,871,447. The U.S. Ser.No. 11/670,856 application claims priority to U.S. Provisional PatentApplication No. 60/743,229 entitled “SYSTEM AND METHOD FOR MANUFACTURINGA THERMAL BATTERY” filed Feb. 3, 2006. These prior applications areincorporated by reference in their entirety.

FIELD OF INVENTION

The present invention generally relates to thermal batteries, and moreparticularly, to automated thermal battery manufacturing systems andmethods.

BACKGROUND OF THE INVENTION

Thermal batteries are primary reserve batteries that utilize anelectrolyte that, at ambient temperatures, is a nonconductive solid.Thermal batteries are characterized as providing a large amount ofenergy relative to their volume. These batteries, if hermeticallysealed, can be stored for a long period of time (in many instancesgreater than ten years) without substantial degradation of performance,and can perform without preliminary preparation in many differentenvironments. Thus, thermal batteries are a desirable source of power ina number of different applications. Once activated, a thermal batterysupplies electric power to a device for time periods ranging from a fewseconds to an hour or longer. No maintenance is required for a thermalbattery during storage prior to use, which permits it to be permanentlyinstalled in devices that themselves may experience long periods ofstorage before use. For example, thermal batteries are used in missilesystems such as Joint Direct Attack Munition (JDAM), Stinger, Javelin,BAT smart missiles, as well as other systems such as aircraft ejectorseats, and sonar buoys.

The configuration of a thermal battery is dictated by mechanical andthermodynamic considerations and is typically a right circular cylinderknown as a “cell stack.” Mechanically, since the components are rigidand brittle, the stack is sealed under mechanical pressure for dynamicenvironment considerations such as shock, vibration, and acceleration.

Thermal batteries contain materials that generally are inert andnon-conductive until the battery is activated. Upon activation, thematerials become molten and highly conductive. This allows the cathodeto interact with the anode. The thermal battery materials are activatedby igniting the battery. For example, a mixture of iron powder andpotassium perchlorate preferably is used to ignite a battery. Onceactivated, the battery may continue to perform until the active materialis exhausted or until the battery cools below the melting point of theelectrolyte.

The typical thermal battery has been constructed using manualtechniques. The conventional wisdom has been that many of the taskscould not be performed adequately via automation and machine. However,human error and variability may also result from manual manufacturingtechniques. Furthermore, manual processing is typically slow. Moreover,there exists a need for improved testing methods. Thus, additionalsystems, methods, and devices are needed to facilitate the manufactureof thermal batteries.

SUMMARY OF THE INVENTION

In accordance with various aspects and embodiments of the presentinvention, an automated system for producing thermal batteries comprises(i) a press system having a rail and shoe system, which is adapted toform pellets from a powder material, (ii) a stacking system associatedwith the press system, which stacking system is configured to selectpellets from storage containers and stack the pellets in a predeterminedorder, and (iii) an enclosing system associated with the stackingsystem, which enclosing system is configured to hermetically enclose thestacked pellets. In accordance with one aspect of an exemplaryembodiment, the press system includes an automated servo press systemadapted to receive a powder material, lay down one or more layers of thepowder material, and press the layer(s) of powder material into a pellet(such as, for example, an anode or cathode pellet).

In accordance with another aspect of an exemplary embodiment of theinvention, the storage containers utilized in connection with thestacking system are pucks, and the press system is configured to sortpellets into more than two pucks such that each puck contains pelletsthat are similar in material, weight, density, and/or thickness.

In accordance with another aspect of an exemplary embodiment of theinvention, the stacking system is configured to select appropriatepellets from the storage containers for forming a thermal battery and tostack the selected pellets on a stacking fixture, wherein the stackingsystem selects pellets based on weight, thickness, material, and/ordensity. In accordance with an exemplary embodiment, the press systemand stacking system utilize a positive air pressure pellet carrierdevice configured to use the Bernoulli principle to lift and transportpellets.

In accordance with yet another aspect of an exemplary embodiment, theenclosing system is configured to laser weld a seam between a thermalbattery container (e.g., a metal cylinder or “can”) and a thermalbattery cap when the container and cap are pressed together.

In accordance with another exemplary embodiment, the automated systemmay include an inventory system designed to track, store, and retrievepellets according to user specifications.

In accordance with another exemplary embodiment, a method ofmanufacturing a thermal battery includes the steps of pressing pelletswith an automated pellet press, stacking the pellets in a predeterminedorder using a positive air pressure pellet carrier device, and enclosingthe stacked pellets to form a thermal battery.

In accordance with another exemplary embodiment of the invention, amethod for pairing pellets in a thermal battery assembly includes thesteps of (i) sorting a plurality of pellets into at least a first groupand a second group, wherein the first group comprises pellets having atleast one of a first weight range, a first thickness range, and a firstdensity range, and wherein the second group comprises pellets having atleast one of a second weight range, a second thickness range, and asecond density range; wherein the first weight range is a differentrange than the second weight range, the first thickness range is adifferent range than the second thickness range, and the first densityrange is a different range than the second density range, and whereinthe pellets of the first group and the second group comprisesubstantially the same material; (ii) selecting at least a first pelletfrom the first group; (iii) selecting at least a second pellet from thesecond group; and (iv) assembling a thermal battery comprising the firstpellet and the second pellet, wherein the first pellet and the secondpellet are selected relative to each other such that at least one of anaverage weight, an average thickness, and an average density of thethermal battery is within a desired average range.

In accordance with still another exemplary embodiment of the invention,a system for producing a thermal battery includes (i) a press systemconfigured to form pellets from a powder material, wherein the presssystem is configured to sort pellets into at least two groups, whereineach group comprises pellets of substantially the same material andcomprises pellets that substantially share at least one of the followingmaterial characteristics: weight, density, and thickness; (ii) astacking system associated with the press system, the stacking systemconfigured to select pellets from the at least two groups and to stackthe selected pellets in a predetermined order, wherein the pellets areselected from the at least two groups relative to each other such thatat least one of an average weight, an average thickness, and an averagedensity of the thermal battery is within a desired average range; and,(iii) an enclosing system associated with the stacking system, whereinthe enclosing system is configured to enclose the stacked pellets withina container, and wherein at least one of the press system, the stackingsystem, and the enclosing system is substantially automated.

In accordance with still another exemplary embodiment, a system totrack, store, and/or retrieve thermal battery components comprises (i) aplurality of storage containers configured to hold a plurality ofpellets, wherein each storage container is associated with a uniqueidentifier, and wherein each unique identifier is associated withinformation describing characteristics of one or more thermal batterypellets stored in the storage container; (ii) a unique identifierreading device comprising circuitry to read the unique identifier; and(iii) a tracking device configured to track a plurality of thermalbattery pellets as the thermal battery pellets are manufactured, whereinthe tracking device is configured to associate the location of thepellets with the unique identifier.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the drawing Figures, wherein like reference numbersrefer to similar elements throughout the drawing Figures, and:

FIG. 1 is a block diagram overview of an exemplary thermal batterymanufacturing system;

FIG. 2 is a flow diagram showing an exemplary thermal batterymanufacturing method;

FIG. 3 is a block diagram of an exemplary stacker device;

FIG. 4 illustrates an exemplary positive air pressure pellet movingdevice;

FIG. 5 illustrates an exemplary puck in perspective view;

FIG. 6 is a flow diagram showing an exemplary automated storage andretrieval method within an exemplary thermal battery manufacturingmethod;

FIG. 7 illustrates a perspective view of an exemplary stacking assembly;

FIG. 8 illustrates an exemplary wrapping assembly;

FIG. 9 is a block diagram of an exemplary method of pairing pellets; and

FIG. 10 illustrates a block diagram of an exemplary automated sealingsystem.

DETAILED DESCRIPTION

While the exemplary embodiments herein are described in sufficientdetail to enable those skilled in the art to practice the invention, itshould be understood that other embodiments may be realized and thatlogical and mechanical changes may be made without departing from thespirit and scope of the invention. Thus, the following detaileddescription is presented for purposes of illustration only and not oflimitation.

In accordance with various exemplary embodiments of the invention, athermal battery manufacturing system and method are configured tofacilitate the automated manufacture of thermal batteries. Furthermore,the thermal battery manufacturing system is configured to facilitatetesting of thermal batteries, storage of thermal battery components,transportation of thermal battery components, pairing of pellets, and/orimproving hermeticity. Moreover, the systems and methods may facilitateproduction of high quality thermal batteries facilitate an increase inthe quantity of thermal batteries produced and/or the efficiency ofmaking such batteries. Furthermore, the cost of making thermal batteriesmay be reduced through use of the systems and methods described herein.

In one exemplary embodiment of the present invention, and with referenceto FIG. 2, an exemplary thermal battery manufacturing method 200comprises the steps of: pressing powder into pellets (step 210),stacking pellets (step 220), enclosing the stacked pellets to complete athermal battery (step 230), testing the thermal battery (step 240),and/or tracking components and related data (step 250).

In accordance with one aspect of an exemplary embodiment of the presentinvention, the thermal battery manufacturing system comprises a presssystem, a stacking system, an enclosing system, a test system and/or atracking/storage/retrieval system. With reference to FIG. 1, anexemplary thermal battery manufacturing system 100 comprises a presssystem 110, a stacking system 120, an enclosing system 130, a testsystem 140 and/or a tracking/storage/retrieval system 150.Tracking/storage/retrieval system 150 may, for example comprise anautomated storage and retrieval system (“ASRS”).

In accordance with one aspect of an exemplary embodiment of the presentinvention, press system 110 is configured to be placed to press powderto create pellets (step 210). The pellets preferably are configured tobe placed within a thermal battery. Although the pellet is describedherein as a flat, round and thin pellet, it should be appreciated thatthe pellet may be formed into any one of various shapes. In accordancewith another aspect of an exemplary embodiment of the present invention,pressing the powder material (step 210) further includes the steps of:pouring the powder material, stamping the powder material into a thinpellet, verifying the quality of the pellet, and/or loading the pelletinto a carrier (referred to herein as a “puck”).

With reference now to FIG. 3, a press system 110 may comprise anycomponents that are configured to receive a powder material, to lay downa layer of the powder material and to press the layers of powdermaterial into a pellet. In accordance with various aspects of anexemplary embodiment, press system 300 is configured to form pellets bypressing the powder material into a pellet having a substantiallyconsistent size, weight, density, thickness, and/or the like. Presssystem 300 preferably is further configured to produce pellets quicklyand with a high likelihood of meeting quality control criteria. Inaccordance with one aspect of an exemplary embodiment, creating pelletsof a consistent density, weight and thickness may facilitate reducinghot spots in the thermal battery. Stated otherwise, pellets havingconsistent material properties (such as weight, density, thickness, andthe like) tend to facilitate assembling a thermal battery having an evendistribution of material throughout the battery, and thus an eventemperature distribution when the battery is fired.

In accordance with an exemplary embodiment, and with continued referenceto FIG. 3, press system 300 comprises a hopper 310, a “shoe” 320, a dieset 330, a rail system 325, and/or punch tooling 340. Hopper 310preferably is configured to receive a powder material. For example,powder material preferably is fed into hopper 310 from bags, jars,and/or other similar containers. Hopper 310 preferably is alsoconfigured to supply powder shoe 320 with the powder material.

In accordance with one aspect of an exemplary embodiment of the presentinvention, shoe 320 is configured to receive the powder material and todispense a quantity of powder into punch tooling 340. In accordance withanother aspect of an exemplary embodiment, shoe 320 is configured toslide forward and backward on rail system 325. The shoe may, for examplesupply a layer of powder as it moves forward across die set 330, andeven out the layer of powder as it moves backwards on rail system 325.Shoe 320 may also be configured to move forward and backwards or side toside multiple times, creating a “shake,” to further even out the layerof powder. Furthermore, press system 300 preferably comprises devicesthat are configured to perform ‘tapping,’ ‘shaking,’ or ‘vibration,’ tofurther even out the layer of powder. In accordance with yet anotheraspect of an exemplary embodiment of the present invention, press system300 is configured to push the newly created pellet from die set 330 andtransport the pellet down a slide, via conveyor belt, and/or via othermethods of transporting a pellet away from the die set area of press300.

In accordance with yet another aspect of an exemplary embodiment of thepresent invention, press system 300 does not comprise any systems thatare cantilevered or that have pivots. Furthermore, any other powdersupplying systems may be used that tend to facilitate spreading a powderwith a level surface, even pressure, and/or consistent powder thickness.

In accordance with one aspect of an exemplary embodiment of the presentinvention, punch tooling 340 is configured to press the powder into athin pellet. Punch tooling 340 preferably facilitates consistency (i.e.,tighter tolerances) in pellet thickness, density, weight, and/or thelike. The press servo, in an exemplary embodiment, utilizes electronicfeedback systems to control positional accuracy to a finer degree thanpreviously available with known art. This improves press repeatabilityfor position, which in turn reduces the tolerance of the compressedpellet thickness. Punch tooling 340 preferably is configured to subjectthe powder to a pressing force of, for example 20 tons to 175 tons.However, other forces may be used, and pressing forces may vary frompowder to powder.

In one exemplary embodiment, punch tooling 340 comprises a top punch anda bottom punch that are preferably configured to move toward each otherto press the powder material into a pellet. In an exemplary embodimentof the present invention, the press is a hydraulic press, a servo press,and/or the like. The pressing of the powder into a pellet may takeplace, for example, in an argon gas environment; however, nitrogenand/or other environments may be utilized.

Furthermore, any press system may be used that tends to facilitateachieving tighter tolerances, a more consistent thickness of the powderlayer, and evenly pressed pellets. The ability to achieve tightertolerances may facilitate stacking more pellets within the same heightof stacked pellets. Thus, use of a servo press and/or rail driven powdershoe may tend to facilitate adding more cells to a thermal batterycompared to prior art thermal battery manufacturing methods involvinghydraulic presses. This results in more consistent pellet thicknesses,which allows designs with more cells to be built because prior artbattery designs were size limited taking into account the possibletolerance inconsistency of the old art presses. Tighter tolerances mayalso permit an equal sized battery to provide more power, due to theincrease number of pellets that may fit in one space. By improvingtolerances by 60% it is possible to achieve 5% greater power from samesized thermal battery due to the addition of another cell in the samecontainer size. Tighter tolerances may also facilitate manufacturing anequal powered thermal battery that is smaller in size. For example, byimproving tolerances by 60%, it may be possible to produce a 1% shorterthermal battery.

The powder material may comprise any number of chemicals or compositionsthat are now known, or that are later discovered to be useful materialsin thermal batteries. For example, the powder material may comprisesubstances such as lithium/aluminum and lithium/silicon (anode), andiron disulfide—FeS₂ (cathode). Other powder materials may compriseelectrolytes, such as combinations of one or more of lithium fluoride,lithium bromide, magnesium oxide, lithium chloride, and/or the like.Another exemplary powder material is a pyrotechnic material or the like.Thus, the powder materials may comprise any substances that can beformed into pellets of the following types: anode, cathode, electrolyte,pyrotechnic, and an electrode (e.g., a stainless steel disk, 3-5thousandths of an inch thick).

In accordance with one aspect of an exemplary embodiment, the cathodepellets may be produced from a variety of materials, such as calciumchromate (CaCrO₄), potassium dichromate (K₂Cr₂O₄), potassium chromate(KCr₂O₂), lead chromate (PbCrO₄), metal oxides such as vanadiumpentoxide (V₂O₅) and tungsten trioxide (WO₃), and sulfides such ascupric sulfide (CuS), iron disulfide (FeS₂), and cobalt disulfide(COS₂). A preferred material is iron disulfide powder mixed with minorportions of an electrolyte salt mixture and optionally binder materialsuch as magnesium oxide. Iron disulfide and cobalt disulfide arepreferred for use with lithium-containing anodes because of chemicalcompatibility.

In accordance with another aspect of an exemplary embodiment, the anodepellets may be made of calcium metal or magnesium metal, but lithiummetal and lithium-aluminum or lithium-silicon alloys are preferred. Forexample, compounds such as LiSi, LiAl, LiAlSi, and LiAlFe may be used inthe anode pellets (which compounds are understood to include all alloysof Li, Al, and Si in varied proportions). As described in detail herein,the lithium-aluminum and lithium-silicon alloys are processed intopowders and cold-pressed into wafers or pellets.

Pressing the powder into a pellet (step 210) may further include thesteps of verifying the quality of the pellet. For example, the pelletmay be manually inspected. However, manual weighing and measuring maytend to suffer from human inaccuracies, breakage due to manual handling,and slowness. Often, due to breakage and time considerations, manualinspection involves sampling measurements and attributing the results ofthe sample to all of the pellets. As such, tolerances tend to be largerwith manual measuring than with automated methods. Furthermore, thepellets tend to be fragile and manual inspection and handling of pelletstends to increase the likelihood of breaking, chipping, or otherwisedamaging the pellets. Moreover, without performing quality checks oneach pellet, the odds may increase that several relatively heavierpellets are used in one part of a thermal battery, thus causing a hotspot.

In accordance with various aspects of exemplary embodiments of thepresent invention, the pellet quality control (“QC”) system isconfigured to inspect the quality of the pellet in an automated manner.In accordance with another aspect, a QC device 350 is configured toautomatically weigh a pellet, measure its thickness, and visuallyinspect the pellet. In one exemplary embodiment, QC device 350preferably is also configured to receive pellets from the press in anautomated manner, such as from a conveyor belt.

Thus, in accordance with one aspect of an exemplary embodiment of thepresent invention, QC device 350 is configured to automatically weighindividual pellets. In this regard, QC device 350 may comprise a digitalscale, or the like. For example, a Mettler Toledo electronic weighingmodule may be used. Other devices may also be used to weigh individualpellets.

In accordance with another aspect of an exemplary embodiment of thepresent invention, QC device 350 is configured to automatically measurethe diameter and/or thickness of individual pellets. In accordance withone aspect of the invention, for example, QC device 350 may include aLinear Voltage Distance Transducer (“LVDT”). Furthermore, other devicesmay be used to automatically measure the thickness of individualpellets. QC device 350 may further be configured to determine the pelletdensity. For example, based on the thickness and the weight of thepellet, QC device 350 may be configured to calculate the density of thepellet.

QC device 350 also is preferably configured to visually inspect apellet, scan one or both sides of the pellet, determine if anysignificant chips, cracks, other structural flaws and/or incompletenessexist in the pellet, verify the ‘roundness’ of the pellet, identify anyedge cracks in the pellet, and/or the like. Thus, in one exemplaryembodiment of the present invention, QC device 350 also preferablyincludes a vision system such as a DVT LEGEND series camera. QC device350 may also comprise, however, any other devices that are configured toautomatically determine the weight, thickness, size, density, and/orstructural integrity of each pellet.

In accordance with various aspects of an exemplary embodiment of thepresent invention, system 100 is configured to group pellets of the sametype based on a material characteristic of the pellet. For example,individual cathode pellets may be grouped or classified according totheir weights, thicknesses, densities, and the like. In this example,pellets that are within acceptable tolerances may nonetheless have smallvariations in their weight, thickness, or density.

Thus, system 100 preferably is configured to classify individual pelletsas light pellets, average weight pellets, and heavy pellets. Moreover,the pellets may be classified into many different categories of pelletweights. For example, pellets may be categorized according to light andvery light ranges. These categories may be defined by the weight rangeassociated with each category. The weights applicable to each range mayvary, but in one example, a pellet weighing 20.9 grams is classified asa heavy pellet and a pellet weighing 20.1 grams may be classified as alight pellet. These categories may alternatively be defined relative toeach other, for example, where some categories are relatively lighter orheavier than other categories.

In one exemplary embodiment, the pellets are sorted by weight, or inother words, the pellets are sorted into groups of pellets that sharethe same weight range or classification. Thus, for example, QC device350 is configured to classify pellets of the same type based on theirweight and to sort those individual pellets into groups associated withtheir individual classification.

Similarly, system 100 preferably is configured to classify individualpellets as thin pellets, average thickness pellets, and thick pellets.Moreover, the pellets may be classified into many different categoriesof pellet thicknesses. For example, pellets may be categorized accordingto thin and very thin ranges. These categories may be defined by thethickness range associated with each category. The thickness applicableto each range may vary, but in one example, a pellet having a thicknessof 12 thousandths of an inch is classified as a thin pellet and a pellethaving a thickness of 30 thousandths of an inch is classified as a thickpellet. These categories may alternatively be defined relative to eachother, for example, where some categories are relatively thinner orthicker than other categories.

The pellets may also be sorted by thickness, or in other words, thepellets may also be sorted into groups of pellets that share the samethickness range or classification. Thus, for example, QC device 350 isconfigured to classify pellets of the same type based on their thicknessand to sort those individual pellets into groups associated with theirindividual thickness classification. Thus, groups of pellets may becreated that share the same thickness characteristic (e.g., thick,average, thin). Similarly, in another exemplary embodiment, QC device350 is configured to classify and sort individual pellets into groupsassociated with their individual density classifications.

Furthermore, QC device 350 preferably is configured to identify pelletsthat fall outside of acceptable criteria or that are outside ofspecified tolerances for pellet weight, thickness and/or densitytolerances, based on the determined weight, thickness, and/or density.For example, a pellet weighing less than an acceptable amount or morethan an acceptable amount preferably is classified as being within arejected range. In another example, pellets that are too light, toothin, or incompletely formed preferably are identified as such. Theidentified pellets may further be marked, redirected, sent to a rejectbin, and/or discarded. Moreover, in accordance with one aspect of theinvention, the results of the tests are recorded for future analysis.For example, data with respect to characteristics such as weight,thickness, density, the presence of cracks, and/or like data, preferablyare stored digitally in a database.

In accordance with various aspects of an exemplary embodiment of thepresent invention, system 100 and/or QC device 350 comprise a databaseor other system for recording information related to a pellet. QC device350 is preferably associated with press system 110 and with stackingsystem 120. QC device 350, in exemplary embodiments, further comprises arobotic pellet moving device. For example, the QC system preferablyincludes a positive air pressure pellet moving device. However, the QCsystem may comprise any other pellet moving system and may also beassociated with any portion of the thermal battery manufacturing system.

The ability to measure or determine the weight, thickness, and/ordensity of each and every pellet and to track such pellets opens thepossibility of purposefully selecting pellets for placement in thethermal battery based on variations in the individual pellet's weight,thickness, and/or density. Thus, in accordance with one aspect of anexemplary embodiment of the present invention, the thermal batterymanufacturing system is configured to assemble a thermal battery byselecting a pellet based not only on its material type, but also byselecting from among more than one category of pellet of its same type.For example, a cathode pellet may be selected from among two groups ofcathode pellets, where one group includes pellets that are relativelyheavier than the pellets in the other group.

In accordance with another aspect of an exemplary embodiment of thepresent invention, the QC device is not only configured to select thepellets based on their weight, thickness, and/or density characteristic,but to perform pellet pairing. Pellet pairing may include any method ofcombining two or more such selected pellets within a thermal battery.

With the pellets sorted into groups by weight, system 100 preferably isconfigured to selectively combine pellets of different weights duringthe stacking of the pellets to form the thermal battery. The pellets maybe selected, for example, such that within a thermal battery or within asingle cell, a heavy pellet is paired with a light pellet. Furthermore,if more than two weight categories are used, additional pairings orcombinations of pellets may be used. Thus, pellet pairing may beconfigured to facilitate construction of thermal batteries having apredetermined weight and/or to maintain an even distribution of pelletmaterial throughout a particular thermal battery or cell.

Thus, in an exemplary embodiment, pellet pairing comprises selectingpellets from groups of pellets, where at least two groups of pelletshave weight characteristics that are different from each other. Forexample, pellet pairing comprises selecting pellets from a group ofheavy pellets and pairing them with pellets selected from a group oflight pellets. However, in accordance with another exemplary embodiment,pellets of different weight ranges are identified and shuffled together,such that selecting the pellets in order is likely to provide an evendistribution of pellet material.

Similarly, system 100 may selectively incorporate pellets of differentthicknesses into a thermal battery. The pellets may be selected, forexample, such that within a thermal battery, or within a single cell, athick pellet is paired with a thin pellet. Furthermore, depending on thethicknesses and number of thickness classifications, any number ofpellets may be matched or combined in any particular order. Thus, pelletpairing preferably facilitates the manufacture of thermal batterieswherein the total thickness of each stack of pellets in the thermalbattery or in a cell can be predetermined and consistently achieved inpractice. Furthermore, pellets of various thicknesses may be shuffledtogether in a single group such that selecting the pellets in order islikely to provide an even distribution of pellet material.

In a similar manner, pellet pairing may be based upon pellet densities.Furthermore, in accordance with another aspect of an exemplaryembodiment of the present invention, pellet pairing may be implementedthrough pairing based on a combination of the weight, thickness, anddensity of the individual pellets. Furthermore, in accordance withvarious aspects of an exemplary embodiment of the present invention,pellet pairing is configured to create a thermal battery having apredetermined weight, thickness, and/or density of that type of pelletin the thermal battery or in cells of the thermal battery. The pelletpairing may also be configured to reduce hot spots in the thermalbattery. Furthermore, other methods or devices may be used that areconfigured to place a pellet in a thermal battery assembly based on itstype and based on the individual pellet's weight, thickness, or densityclassification.

In accordance with one aspect of an exemplary embodiment of the presentinvention, a method of pellet pairing comprises determining the weight,thickness, and/or density of a pellet (step 910). The determinationpreferably is made by measurement, calculation, and/or the like. Thedetermined weight, thickness, and/or density are compared to standardsfor that determined value (step 920). Based on this comparison, thepellet is categorized/classified (step 930). The pellet may further bephysically grouped together with other pellets that share the samecategory/classification (step 950). For example, the pellets preferablyare sorted into storage containers, with each storage container holdingone category of pellet.

During assembly of a thermal battery, the pellets are retrieved for usein building the thermal battery. In accordance with one aspect, morethan one group of pellets of the same type, each having a differentcategory of pellets, is selected (step 940) and delivered to the thermalbattery assembly area. In one exemplary embodiment of the presentinvention, a pellet is selected from a first group having a firstmaterial characteristic (step 951). If that first group, for example,includes pellets that are ‘light’, a pellet is selected from a secondgroup having a second material characteristic (step 952), where pelletsin that group are ‘heavy’. If that first group instead includes pelletsthat are ‘heavy’, a pellet is selected from a third group having a thirdmaterial characteristic (step 953), where pellets in that group are‘light.’ In either instance, the pellets are paired, or in other wordsone of each type of pellet is added to the thermal battery (step 960)such that the combination achieves a desired result. By way of example,assembling the thermal battery preferably comprises the steps ofselecting one pellet that is less than the average individual pelletweight, thickness, or density, and selecting another pellet from a groupof pellets having a greater than average individual pellet weight,thickness, or density. The selected pellets are added to the thermalbattery (step 960).

In accordance with another aspect of an exemplary embodiment of thepresent invention, system 100 comprises a positive air pressure pellettransport device or similar pellet moving device, a device configured tosort pellets into groups of pellets based on a material characteristicof a type of pellet and to select from sorted groups of pellets toassemble a thermal battery. System 100 preferably further comprises apuck or similar device configured to hold a group of pellets having acommon material characteristic, an ASRS or similar system forcontrolling the measuring, sorting, selecting, and stacking stepsdescribed in connection with pellet pairing and quality control. In oneexemplary embodiment, the positive air pressure carrier is configured toautomatically select individual pellets in a specific order based onmaterial characteristics of the groups. Furthermore, a pellet pairingthermal battery assembly system may comprise any devices configured tofacilitate increased power output, smaller batteries, and/or that tendto reduce the occurrence of “hot spots” by reducing the occurrence ofseveral particularly thick, dense, or heavy pellets being stacked inproximity to each other.

In accordance with various aspects of an exemplary embodiment of thepresent invention, the thermal battery assembly system is configured tomove individual pellets from one location to another. In accordance withother aspects, system 100 comprises a positive air pressure pelletcarrier. In accordance with another aspect of an exemplary embodiment ofthe present invention, positive air pressure is used to lift, move, andset down a pellet. A positive air pressure pellet carrier, for example,is further configured to lift pellets of different weight, thickness,and/or density. The positive air pressure pellet carrier is able to liftand move the pellets due to the Bernoulli principle. The Bernoulliprinciple states that in fluid flow, an increase in velocity occurssimultaneously with a decrease in pressure.

In this regard, the positive air pressure pellet carrier preferably isconfigured to adjust the rate of airflow to facilitate lifting pelletsthat have different material properties, such as weight, thickness,density, and/or material. For example, a heavier pellet may be liftedusing a greater rate of airflow compared to a lighter pellet that islifted using a lower rate of air flow. In one example, the positive airpressure pellet carrier is configured to adjust the airflow rate eachtime a different type of pellet (e.g., cathode, anode, heat source,electrolyte) is selected. Furthermore, in an exemplary embodiment, thepositive air pressure pellet carrier is configured to adjust the airflowrate for each pellet selected. For example, the positive air pressurepellet carrier preferably is configured to use a different air flow ratefor one pellet than for another pellet of the same pellet type, wherethe two pellets have dissimilar weights. Furthermore, the positive airpressure pellet carrier preferably is configured to shake off a second,or partial, pellet that was inadvertently lifted with the intendedpellet.

Although the device that moves the pellets is referred to herein as apositive air pressure pellet carrier, it should be understood that thisterm includes other devices that are configured to move pellets. Thepositive air pressure pellet carrier may be configured to move pelletsfrom a first location to a QC station or to a reject bin. The positiveair pressure pellet carrier is preferably configured to load pellets ina carrier device (e.g., a “puck”) that is configured to facilitatetransportation and/or storage of the pellet(s). The positive airpressure pellet carrier is further configured to unload a puck and tomove pellets, one at a time, and stack them in a thermal batteryassembly.

With reference now to FIG. 4, in accordance with one aspect of anexemplary embodiment of the present invention, the thermal batterymanufacturing system comprises a positive air pressure pellet movingdevice 400 (e.g., a so-called Bernoulli gripper). Positive air pressurepellet moving device 400 comprises a head 410 having one or more airnozzles 420 directing air in a generally downward direction, one or morepads 430 on head 410 creating a distance between the nozzle(s) 420and/or a lifted pellet (e.g., 490). Nozzles 420 may have an air flowrate of about 10 to about 3,000, preferably from about 10 to about 300,and optimally from about 20 to about 200. Positive air pressure pelletmoving device 400 may have an air pressure of about 0.1 psig to about120 psig, preferably from about 5 psig to about 70 psig, and optimallyfrom about 10 psig to about 32 psig.

In accordance with one aspect of an exemplary embodiment of the presentinvention, positive air pressure pellet moving device 400 is preferablyfurther configured to remove any additional pellets that might be liftedup by positive air pressure pellet moving device 400 with the intendedpellet. Positive air pressure pellet moving device 400 may further beconfigured to adjust the pressure/air flow rate of the blast of air fromits nozzle(s). For example, positive air pressure pellet moving device400 may be less prone to double select heavier/denser pellets, andtherefore may be configured to use lower pressure air blast for heavierpellets. Thus, positive air pressure pellet moving device 400 preferablyis configured to change the air flow parameters for pellets havingdifferent material properties. In one exemplary embodiment, positive airpressure pellet moving device 400 is equipped with a proportional airvalve that preferably is adjusted for each selected pellet or pellettype. However, device 400 may comprise any device that is configured tolift, move, and set down a pellet 490 using positive air pressure.

In one exemplary embodiment, positive air pressure pellet moving device400 is configured to blow air in a direction perpendicular to andintersecting with the downward air flow of positive air pressure pelletmoving device 400. The perpendicular air flow preferably is configuredto blow below the selected (top) pellet. In an exemplary embodiment, thesideways blast preferably is configured to be provided at from about 25to about 50 psig, however other pressure ranges may also be used.Furthermore, positive air pressure pellet moving device 400 may beconfigured to pulse either the parallel or perpendicular air flow toprevent or rectify selection of more than one pellet.

In accordance with one aspect of an exemplary embodiment of the presentinvention, positive air pressure pellet moving device 400 comprises anair knife 450. Air knife 450 may comprise one or more nozzles 480.Nozzles 480 are oriented to blow perpendicular to the main air flow andbelow a single selected pellet. Thus, air knife 450 preferably isconnected to positive air pressure pellet moving device 400 in such away that it moves in conjunction with positive air positive air pressurepellet moving device 400. Furthermore, in other embodiments, air knife490 is not attached to positive air pressure pellet moving device 400.Furthermore, air knife 450 may include any device that may be used inconjunction with the positive air pressure pellet moving device 400 thatis configured to remove ‘double picks’ and/or the like.

Thus, in accordance with one aspect of an exemplary embodiment of thepresent invention, the method further comprises the steps of: moving thehead 410 of positive air pressure pellet moving device 400 over pellet490, blowing air over the pellet, and while blowing, raising the head.The downward air stream may cause pellet 490 to rise up to pad(s) 430 onhead 410 of Positive air pressure pellet moving device 400.

In accordance with yet another aspect of an exemplary embodiment of thepresent invention, a carrier/container device is configured to receive,move, and/or store one or more pellets. This carrier/container is alsoreferred to herein as a “puck.” The puck preferably is configured tohold and transport a plurality of pellets such that the integrity of thepellets is maintained (e.g., no chipping, breaking, degradation due tohumidity and/or the like).

With reference to FIG. 5, in accordance with one aspect of an exemplaryembodiment, puck 500 comprises a base 530 and a right circular cylinder505. Cylinder 505, for example, is attached to and substantiallyperpendicular to base 530. Right circular cylinder 505 has an innerdiameter at least as large as the diameter of a pellet to be containedtherein. For example, the inner diameter preferably is 10% greater thanthe diameter of a pellet stored in the puck. In other examples, theinner diameter preferably is 7% or 5% greater than the diameter of apellet stored in the puck. Right circular cylinder 505 may also have aheight at least as great as the thickness of two or more pellets to becontained therein. In another example, the height is the thickness ofapproximately 20-40 such pellets. In another example, the height is fromabout 1 to about 10 inches, preferably from about 3 to about 7 inches,and optimally from about 4 to about 6 inches.

Furthermore, puck 500 preferably is any storage device that isconfigured to store and/or transport a group of pellets. Moreover, thediameter and height preferably are any values that facilitate loadingand unloading the pellets using a positive air pressure pellet movingsystem such as a Bernoulli gripper.

In addition, with respect to facilitating use of Positive air pressurepellet moving device 400, puck 500 may further be configured tofacilitate the selection of individual pellets and to reduce thelikelihood of selecting multiple pellets (“double picking”). Puck 500may also be configured to reduce pellet flutter and/or damage to thepellet.

In this regard, and in accordance with one aspect of an exemplaryembodiment, puck 500 includes one or more slots 510. Slot 510, in oneexample, is oriented perpendicular to base 530. However, in otherexemplary embodiments, slot 510 is at an angle to base 530, and/or ismore or less continuous along the height of cylinder 505. Slot 510 mayfurther have a width of from about ⅛ inch to about 2 inches, preferablyfrom about ¼ inch to about 1 inch, or optimally from about ½ inch toabout ¾ inch. In another example, slot 510 may have a width that is afunction of the circumference of cylinder 505. For example, the width ofslot 510 is about 1% to about 10% of the circumference of cylinder 505,preferably about 1% to about 5% of the circumference of cylinder 505, oroptimally about 2 to about 4% of the circumference of cylinder 505.

Moreover, slot 510 preferably is any air passageway of a shape, size,width or configuration that allows air to pass between the area withinthe cylinder and the area external to the cylinder and to facilitatereduction of pellet damage, pellet flutter and/or pellet double picks.

In accordance with other exemplary aspects of the invention, puck 500 isconfigured to store a group of pellets in an environmentally isolatedspace. An “environmentally isolated space” is a volume or space that canbe hermetically, thermally, barometrically, and/or otherwise isolatedfrom adjoining volumes or spaces. Thus, puck 500 is configured tofacilitate the storage of pellets and/or to tend to improve the shelflife of pellets stored therein. For example, puck 500 preferably isconfigured to store pellets under a vacuum in isolation from an externalenvironment. Puck 500 may, for example, be configured to hold a vacuumfrom about −22 inches of mercury to about −29 inches of mercury. Inanother example, the vacuum preferably is from about −25 to about −29inches of mercury or preferably from about −27 to about −29 inches ofmercury. The pellets tend to be hygroscopic and moisture can bedetrimental to the pellet's shelf life. Thus, storing the pucks in avacuum (i.e., hermetically sealed) may tend to facilitate enhanced shelflife of the pellet components of a thermal battery. Shelf life may bedefined in terms of the level of hermeticity. For example, the thermalbattery may meet certain military standards such asMilitary-Standard-1234, known as the Mil-Std-883 test standard methodfor gross and fine leak. The present invention contemplates that thethermal battery is able to meet the Mil-Std-883 as it is currently andto meet it if it is revised by the military in the future.

Furthermore, the puck preferably is configured to facilitate protectionof pellet inventory in the event of loss of environmental control overthe area in which the pellets are created, processed, and/or stored.Pellets may be created, processed, and/or stored within a controlledenvironment, such as, for example, in an environment maintained at fromabout 68 to about 78 degrees Fahrenheit and less than about 1% relativehumidity. However, if control is lost over that environment, the pelletssealed in puck 500 are likely to remain protected. Moreover, puck 500preferably is configured to facilitate shipment of pellets from onemanufacturing location to another, or within a manufacturing locationpassing through non controlled environments.

Thus, in accordance with one aspect of an exemplary embodiment, puck 500further comprises a lid 520 that is configured to create a space withinwhich pellets are stored and isolated from the surrounding environment.Lid 520 may for example, slide over the right circular cylinder 505 andseal against base 530. The seal may, for example be formed with anelastomeric O-ring. Lid 520 may further comprise a pressure gauge 550and a valve 560. Valve 560 may, for example, be a Schroeder type valve(i.e., a standard bicycle tire valve).

Alternatively, valve 560 may comprise any other type of valve configuredto facilitate drawing a vacuum on the sealed puck. Gauge 550 preferablyis any gauge that is suitably configured to indicate the level of thevacuum drawn on puck 500, and the seal preferably is formed using anydevice(s) or techniques know for generating a vacuum tight seal betweentwo objects.

In accordance with one aspect of an exemplary embodiment of the presentinvention, thermal battery manufacturing system 100 comprises anautomatic stacker 120. The automated stacker preferably is configured toreceive product, perform various quality checks on the product received,and facilitate assembly of the thermal battery by automatically stackingpellets.

Automatic stacker 120 is preferably configured to receive more than onetype of pellet. In accordance with one exemplary embodiment, a group ofpellets of one type may be delivered in a puck. Furthermore, automaticstacker 120 preferably is configured to receive a number of pucks. Inthis regard, one puck may contain pellets of a different type thananother puck. In addition, automatic stacker 120 preferably isconfigured to receive a ‘kit’ comprising a plurality of pucks containingthe types of pellets that are used to assemble a thermal battery.

In accordance with one aspect of an exemplary embodiment of the presentinvention, the kit may comprise a tray holding a plurality of pucks.Also, in an exemplary embodiment, the kit is delivered to automaticstacker 120 via a conveyor belt. However, any other systems and devicesfor delivering a plurality of pellets may be used to supply automaticstacker 120 with a source of pellets with which a thermal battery isassembled.

In accordance with another aspect of an exemplary embodiment of thepresent invention, automatic stacker 120 is also preferably configuredto identify the kit and/or pucks that it receives and to off load pucksfrom the kit at the stacker station. For example, automatic stacker 120preferably comprises a bar code reader. However, any other systems anddevices for recognizing a plurality of pellets, for the purpose ofselecting a pellet of a particular type for stacking, may be used.

Automatic stacker 120 (or an optional tracking, storage, and/orretrieval system denoted as an “ASRS” system and described below) mayalso be configured to unseal the pucks. In addition, automatic stacker120 is configured to pick up pellets from the various pucks andautomatically stack the pellets to form part of a thermal battery. Inone exemplary embodiment, an automated stacker 120 is configured toselect a first type of pellet from a first puck and a second type ofpellet, different from the first type of pellet, from a second puck. Inone exemplary embodiment, the pellets of the different types are stackedaccording to a predetermined sequence. By way of illustration only,automatic stacker 120 is configured to assemble one cell of a thermalbattery by placing the following pellets on top of each other in thefollowing order: a lithium anode pellet, an electrolyte pellet, acathode pellet, a heat pellet, and an electrode pellet. Other stackingsequences, however, may be used. In accordance with various exemplaryembodiments of the present invention, the sequence may be repeated aprescribed number of times. Furthermore, it is noted that exemplarypellet stack ups may vary from one section to another or within cells.

Thus, stacker 120 is preferably configured to select pellets from thevarious pucks based on the unique identifier and build a thermal batterybased on pellets received in the kit. Furthermore, stacker 120 ispreferably configured to automatically request the next kit of thermalbattery components to be supplied by the ASRS. This request ispreferably made via a kitting station. In accordance with another aspectof an exemplary embodiment of the present invention, automatic stacker120 is further configured to facilitate pellet pairing as that term isdescribed herein.

In accordance with another aspect of an exemplary embodiment of thepresent invention, automatic stacker 120 is configured to move pelletsusing positive air pressure using Positive air pressure pellet movingdevice 400 or a similar device. Automatic stacker 120 is configured, forexample, to move pellets from a puck to one or more inspection stations,to discard stations, and/or to a stacking location where pellets arestacked to form part of the thermal battery. In addition, automaticstacker 120 is configured to operate under directions from an automatedstorage and retrieval system (described herein) or other similar methodsof control, and under that direction to selectively pick from two ormore carriers to create thermal battery cells.

In accordance with one aspect of an exemplary embodiment of the presentinvention, automated stacker 120 preferably is configured to performvarious quality checks on the pellet. In an exemplary embodiment,automated stacker 120 is configured to perform a vision inspection ofthe pellet. Automated stacker 120 is preferably configured to determinewhether two or more pellets were inadvertently picked up at the sametime, or whether a selected pellet was dropped in transit. Also,automated stacker 120 is preferably configured: to verify that thepellet does not have a crack or other defect; to report errors; to stopthe process, provide an alert, and await operator intervention; todiscard a questionable pellet and select a replacement pellet; and/orthe like. Moreover, the same quality checking is preferably performed onthe replacement pellet. Furthermore, the quality checking may includechecking the weight, thickness and/or density of the pellet.

In accordance with various aspects of an exemplary embodiment of thepresent invention, stacker 120 may comprise a system(s) such as a DVTLEGEND series camera, and/or the like. Moreover, automatic stacker 120may comprise any devices or devices that can be configured to performquality checking of the pellets before assembly in the thermal battery.In an exemplary embodiment, QC device 350 and the method discussed aboveis used to verify the quality of the pellets before they are assembledinto the thermal battery.

Automatic stacker 120 may further comprise a stacking fixture. Thestacking fixture is configured to align the pellets as they are stacked.Furthermore, the stacking fixture preferably is configured to beadjustable to accommodate pellets of different sizes (e.g., diameters.)Automatic stacker is preferably configured to reduce breakage instacking pellets and/or reduce the distance the pellets are dropped.

With reference to FIG. 7, an exemplary stacking fixture 700 may comprisea stacking plate 710 and at least three alignment bars 720. Alignmentbars 720 are connectable to stacking plate 710. Furthermore, alignmentbars 720 are preferably adjustably connected to stacking plate 710. Theadjustment of alignment bars 720 may, for example, be in a radialdirection from the center of stacking plate 710. Furthermore, stackingfixture 700 may comprise an elevator that lowers as pellets are stackedon the elevator, thus lowering the stack of pellets as the pellets beginto be placed on the thermal battery stacking assembly. This system ispreferably controlled via program logic control (“PLC”) and operatespneumatically, hydraulically or electronically.

However, stacking fixture 700 may comprise any device or combination ofstructures that are configured to stack pellets and to facilitatealignment of pellets during assembly of a thermal battery.

In accordance with one aspect of an exemplary embodiment of the presentinvention, the stacked pellets are wrapped (step 130). Wrapping thestacked pellets may facilitate enhanced structural integrity of thethermal battery, reduced breakage of the pellets, insulation of thethermal battery pellets, and electrical insulation.

The enclosing system preferably is configured to apply pressure to thestack of pellets through pneumatic, hydraulic, or servo drive, such thatthe pellets are pressed towards each other. Furthermore, this stack ofpellets is wrapped with a tape. The system is preferably configured towrap the stack of pellets with tape in a semi-automated manner. In oneexample, the stack of pellets is rotated and tape, from a spool, iswrapped around the stack of pellets as it spins. The system is furtherconfigured such that a user can move a spool of tape up and/or down asthe tape winds about the stack of pellets, or this process may beautomated. The system is configured such that the rate of rotation ofthe stack of pellets, pressure on the stack of pellets, and/or thetension on the tape being pulled onto the stack of pellets is controlledin an automated manner, which tends to reduce variations in theconstruction of the thermal battery.

In accordance with one aspect of an exemplary embodiment of the presentinvention, the tape may comprise a fiberglass tape that is preferably0.005″ thick by 0.50″ wide. The tape is preferably covered by Roll A orRoll B weave of tape that meets certain military specifications such asMIL-Y-1140H. The tape may, however, be any tape that is configured tokeep compression on the cell stack (pellets and insulation) to preventcomponent movement (e.g. pellets, leads, mica insulation, thermalinsulation) during induced vibration of the finished battery.Furthermore, and with reference to FIG. 8, wrapper 800 preferablycomprises a tape dispenser 810. Tape dispenser 810 may further comprisea pistol grip. Tape dispenser 810 may be physically attached to thepistol grip such that the two move up and down together. The pistol gripand tape dispenser 810 preferably are attached to an electromagneticclutch that is automatically adjusted as the tape is wound onto thebattery stack. The clutch is automatically adjusted as the tape spoolsruns down to maintain a set tension. The tension, may, for example, bemaintained from about 2 ft-lb to about 80 ft-lb. In another example, thetension may be maintained from about 5 ft-lb to about 50 ft-lb orpreferably from 5 ft-lb to about 25 ft-lb.

Wrapping the stack of pellets may further include the steps ofinsulating the tape wrapped stack of pellets, adding electrical tabs,and/or the like. Furthermore, electrical connections to the tabspreferably are spot welded using stainless steel leads. Other methodsmay also be used to form electrical connections between the segments ofthe thermal battery and the terminals at the top of the battery.Furthermore, any other suitable method of wrapping the stacked pelletsmay be used.

In accordance with another aspect of an exemplary embodiment of thepresent invention, the thermal battery manufacturing system isconfigured to seal the wrapped stack of pellets in a housing. In thisregard, the wrapped stack of pellets preferably is placed inside acylindrical container (or canister) and a header (or lid) is positionedon top of this container. The thermal battery manufacturing system maythen be configured to weld the canister and the lid to each other insuch a manner that the pellet stack is hermetically sealed within thecanister.

In accordance with yet another aspect of an exemplary embodiment of thepresent invention, and with reference to FIG. 10, thermal batterymanufacturing system 100 may comprise an automated sealing system 1000.Automated sealing system 1000 may comprise a base 1010, a collar 1020,and a heat sink comprising a cold plate 1030, a hold 1040, a laser 1050and a weld torch 1060. For clarity, a container 1070 and a header 1080are illustrated in relation to automated sealing system 1000.

In accordance with another aspect of an exemplary embodiment of thepresent invention, automated sealing system 1000 is preferablyconfigured to draw heat away from the header/container during thewelding operation. For example, automated sealing system 1000 ispreferably configured to draw heat from the top of the header and fromthe sides of the container. In addition, system 1000 is optimallyconfigured to provide structural support that tends to inhibit changesin the shape of the container during the welding process. In thismanner, automated sealing system 1000 is also configured to tend toreduce the possibility of cracking the glass seal in the header.

The heat sink comprising cold plate 1030 may further comprise collar1020. Collar 1020 preferably comprises two metal pieces that areconfigured to be placed around container 1060 in the vicinity of thejoint between the header and container. Collar 1020 may further beconfigured to touch the container around the majority of itscircumference. Collar 1020 may further be configured such that anoverlapping clamp configuration tends to reduce the chance of heat buildup at gaps between the two collar pieces. Thus, collar 1020 isconfigured to help maintain concentricity and to draw the heat away fromthe location being welded.

Both cold plate 1030 and collar 1020 preferably are chilled before use,for example, by resting on a cold plate. Cold plate 1030 and/or collar1020 may be placed in contact with the thermal battery just prior to thewelding step, and removed thereafter. In one example, collar 1020 maycomprise two components that are hinged together at one side and heldtogether by a thumbscrew and pin apparatus at the opposite side. The twocollar pieces may further include over-lapping portions where they meet.

Nevertheless, the heat sink may comprise any other devices and systemsthat are configured to remove heat from the location being welded.Furthermore, the heat sink may be any device that provides structuralsupport in the vicinity of the welding.

In accordance with another aspect of an exemplary embodiment of thepresent invention, automated sealing system 1000 is preferablyconfigured to press header 1080 towards container 1070 and to weld theheader to the container. Hold 1040 preferably is configured to bepositioned over header 1060 and to facilitate applying pressure on thecontainer/header assembly. System 1000 preferably is configured tocreate the force that presses hold 1040 into header 1080, which in turnis pressed into container 1070. System 1000 preferably is configured tocreate this pressure through hydraulic or electronic means with apressure of about 50 ft-lb. to about 5000 ft-lb., preferably about 100ft-lb. to about 3000 ft-lb., and optimally of about 100 ft-lb. to about2500 ft-lb. In another example, system 1000 comprises a quality controldevice that is configured to regulate the distance hold 940 moves. Forexample, program logic control preferably is configured to control theforce and relative movement of the press. The program logic control, forexample, is configured to receive feedback from a series of qualitycontrol devices regarding the force and movement of the press and tobase its control in part on that feedback. Thus, automated sealingsystem 1000 preferably is configured to use force and distance controlon the header/container compression. In this manner, automated sealingsystem 1000 is configured to avoid over or under pressing the header anddeforming the assembly.

Thus, in accordance with another aspect of an exemplary embodiment ofthe present invention, automated sealing system 1000 comprises a press.The press may comprise a hydraulic press such as, for example, anEnerpac cylinder-type RD46, or a servo press such as, for example, anAllen Bradley motor, series 7054. Furthermore, other devices forpressing the two portions together during welding may be used. Inaddition, by way of example, the canister and lid are made of stainlesssteel. However, other materials may also be used for the outer casing ofa thermal battery.

Furthermore, automated sealing system 1000 is preferably configured torotate the compressed header/container assembly as the junction betweenthe two pieces is welded. Base 1010 preferably is configured to hold andrevolve the container.

In another exemplary embodiment, automated sealing system 1000 isconfigured to use laser 1050 to detect changes in the distance X betweenweld torch 1060 and the seam being welded. Based on this detected changein distance, system 1000 preferably is configured to make an adjustmentto compensate for this change in distance. For example, laser 1050 ispreferably configured to measure the distance between the laser and thecontainer side. If a container has a minor deviation from a truecircular cylinder, as base 1010 rotates the header/container assembly,the distance between laser 1050 and the circumference of the containerwill change. Laser 1050 is configured to detect such a distance changeand automated sealing system 1000 is configured to move weld torch 1060in or out based on the detected distance changes. In this manner,automated sealing system 1000 is configured such that any irregularitiesor non-concentricity in the container/header seam are not as likely toaffect the distance between weld torch 1060 and the seam.

Thus, in accordance with yet another aspect of an exemplary embodimentof the present invention, automated sealing system 1000 comprises alaser guided weld torch 1060. In one exemplary method, weld torch 1060is positioned at the seam, and backed off a distance X from thecontainer. Furthermore, weld torch 1060 preferably is positioned at anangle theta from perpendicular to the container side. By way of example,distance X preferably is about 0.020″ to about 0.100″, preferably about0.030″ to about 0.080″, and optimally about 0.040″ to about 0.060″.Also, angle theta preferably is about 10° to about 80°, preferably about30° to about 60°, and optimally about 40° to about 50°.

Furthermore, laser 1050 preferably comprises a sensor that is configuredto communicate with the PLC; in turn the PLC adjusts the position of theweld nozzle with respect to the weld seam of the container and header.The sensor is preferably an Optoelectronic sensor.

Additionally, automated sealing system 1000 may comprise servoactuators. The actuators are attached to weld torch 1060. However, theactuators may comprise hydraulic actuators or any other actuators thatare configured to move weld torch 1060. Furthermore, any system may beused that is configured to use a laser to guide a weld torch about theperimeter (whether circular or otherwise) of a container, wherein theweld torch position can be adjusted to maintain a constant distance Xbetween weld torch 1060 and the container/header joint.

Automatic sealing system 1000 preferably is further configured tomaintain other parameters constant. For example, the rotation of thecontainer/header assembly preferably is configured to be at a constantspeed. For example, the rotation speed is about 0.001″/sec to about2.000″/sec, preferably about 0.010″/sec to about 0.750″/sec, andoptimally about 0.010″/sec to about 0.250″/sec. Automatic sealing system1000 may also be configured to maintain a constant pulse rate, and/orthe temperature. Furthermore, automated sealing system 1000 preferablyis configured to adjust such parameters to account for variations inother parameters.

A typical prior art thermal battery had a 75% to 90% chance of passingthe gross and fine leak tests the first time they were tested. Althoughvarious standards are established for ‘passing’, in one exemplarystandard, a thermal battery that holds a vacuum down to 1.times.10-7cc/atm is a passing thermal battery and will have a shelf life ofapproximately twenty years. In accordance with another aspect of anexemplary embodiment of the present invention, a product's specificationdefines the passing criteria for fine leak. Any leak greater than thespecified value is determined to be a ‘leak failure.’ Passing standardsand testing techniques are further defined in Mil-Std-883, method 1014,gross leak and fine leak testing.

In accordance with an aspect of an exemplary embodiment of the presentinvention, the automated welding process is configured to facilitateimproving the first pass rate from about 85% to about 98% or higher.Thus, an exemplary thermal battery produced by the automated sealingprocess of thermal battery manufacturing system 100 has at least a 98%chance of passing the gross and fine leak tests. This represents asubstantial improvement over the prior art in the pass rate of a thermalbattery. Thus, a thermal battery manufactured with the sealing systemdescribed herein is a new thermal battery having the property of being98% likely to pass a hermeticity test. Furthermore, the thermal batterypreferably has the property of having an aesthetically pleading weld.Moreover, the speed of welding may be improved by 30% over conventionalwelding in thermal battery construction.

In accordance with exemplary embodiments of the present invention, thethermal battery manufacturing system is configured to perform one ormore tests on the thermal battery (step 240). Thermal battery testingpreferably is configured to verify the hermetic seal, confirm that thereare no shorts or opens, verify the integrity of all connections, verifythat dimensional tolerances are satisfied, and/or detect any deviationsfrom specifications.

The testing comprises non-destructive or destructive testing. Exemplarynon-destructive testing may include: a hermetic seal test, an x-raytest, a capacitance/inductance test, a resistance test, a squibresistance test, an insulation resistance test, a polarity test, and/orthe like. Non-destructive testing may further include dimensionaltesting to verify that the size, length, and relational dimensions arecorrect.

The hermetic seal test may comprise a gross leak test and/or a fine leaktest. The gross leak test, for example, may comprise the steps ofplacing the thermal battery in a chamber and purging the chamber withhelium for thirty minutes, then placing the thermal battery in a hotwater bath. In this exemplary gross leak test, visible bubbles mayindicate an ineffective seal.

The fine leak test, for example, may comprise the steps of placing thethermal battery in a chamber and purging the chamber with helium forthirty minutes, then after removing the external helium source, a‘sniff’ test is performed. Detection of helium by the “sniff” test mayindicate an ineffective seal. The “sniff” test may be useful fordetecting relatively small leaks. An ineffective seal often isdetrimental to shelf life. Furthermore, testing (step 240) comprises anymethod for verifying that the thermal battery is sealed to within thestandards specified for that particular thermal battery.

In accordance with an exemplary embodiment of the present invention, thethermal battery is tested through non-destructive x-raying of thethermal battery. In addition, other X-ray testing methods and devicesmay be used to facilitate performing a quality check on a thermalbattery.

In accordance with another aspect of an exemplary embodiment, thetesting (step 240) may further comprise capacitance testing. Capacitancetesting preferably is configured to distinguish between “in family” and“out of family” thermal batteries. An “in family” battery is a thermalbattery that satisfies standards and/or specifications for that type ofthermal battery. Furthermore, “in family” thermal batteries of the sametype will generally have similar capacitance test results when testedunder the same conditions. In contrast, an “out of family” thermalbattery may have substantially different test results from “in family”thermal batteries, even when tested under the same conditions. An “outof family” thermal battery preferably is a thermal battery that isoutside of quality control standards and/or specifications.

Briefly, capacitance testing may comprise one or more of the followingsteps: connecting the thermal battery in series with a resistance;connecting the thermal battery and resistance in series with asinusoidal voltage source; applying a sinusoidal voltage to the thermalbattery, measuring an impedance across two terminals of the thermalbattery, comparing the measured impedance to a reference impedance; andindicating whether the tested thermal battery is “in family” or “out offamily.” For further information regarding capacitance/inductancetesting, see U.S. patent application Ser. No. 11/162,061 (filed on Aug.26, 2005), which is incorporated herein in its entirety by reference.Although described herein as capacitance testing, inductance orreactance measurements may also be suitably used in this test. Thus,testing (step 240) may comprise any test that uses capacitance,inductance, or reactance measurements to distinguish between “in-family”and “out of family” thermal batteries.

In accordance with another aspect of an exemplary embodiment, thetesting (step 240) may comprise resistance testing. A resistance testmay be configured to verify that there are no shorting paths. Forexample, in a Squib resistance test (e.g., 0.9-1.9 Ohms) a relativelysmall voltage (0.25 V) at a very low current (approximately 1 mA) isplaced across the thermal battery squib terminals, and the resistance ofthe squib is analyzed. In this test, the Amps across the thermal batterysquib terminals are not large enough to fire the battery, but mayindicate whether a short exists. Similarly, an insulation resistancetest may be configured to verify that there are no shorting paths. Thistest measures the resistance from pin to case (100 Mohms) when 500 VDCis applied and pin to pin (1 Mohms) when 250 VDC is applied.

Testing (step 240) may further comprise a polarity test. Testing mayalso comprise dimensional tests, or in other words, verifying thatvarious components of a thermal battery are within specified ranges forsize, length, relative distances, and/or the like. In this regard,distances are measured to verify that the thermal battery's dimensionsare within specified tolerances. Moreover, testing (step 240) maycomprise destructive tests, where the battery is fired and the outputand other characteristics of the battery are recorded.

Thus, testing (step 240) may comprise any testing that is configured toidentify thermal batteries that are or are not within specifications,tolerances, and/or QC standards. Furthermore, the results of one or moretests preferably are captured, stored, and analyzed. These resultspreferably are captured using any standard data acquisition or manualinput method. These results may also be stored using a database or othersimilar system for storing/analyzing data.

In accordance with one aspect of an exemplary embodiment of the presentinvention, system 100 comprises a tracking, storage, and/or retrievalsystem (“ASRS”) 150.

ASRS 150 preferably is configured to track pellets as they move throughthe thermal battery manufacturing process. Furthermore, ASRS 150preferably is configured to facilitate automatically retrieving pelletsfrom storage and/or making kits for facilitating construction of athermal battery. Moreover, ASRS 150 may be configured to facilitateimproved data collection and analysis regarding the thermal batterymanufacturing process.

In accordance with one aspect of an exemplary embodiment of the presentinvention, a group of pellets are associated with a unique identifier.For example, puck 500 preferably is associated with a unique identifier.The unique identifier may be a bar code, a number, a color, and/or thelike. The unique identifier is configured to be associated with datathat is relevant to thermal batteries and/or the thermal batterymanufacturing process.

The unique identifier preferably is associated with the puck by, forexample placing a sticker with the bar code on puck 500, etching a barcode on puck 500, and/or the like. In other embodiments, a radiofrequency (RF) device is attached to puck 500 for communicating theidentifier via RF signals. Furthermore, other methods of identifying anobject may be used.

ASRS 150 is also preferably configured to track, based on one or moreunique identifiers, the location of the group of pellets. In accordancewith another aspect of an exemplary embodiment of the present invention,ASRS 150 is configured to facilitate inventory management with respectto the pellets used in assembling a thermal battery. For example, ASRSmay keep track of the number of pucks that are available for use inkits, the number of pucks that are being prepared at that time, and thenumber of requests for thermal batteries. ASRS may further usepredictive analysis or other input to determine future needs.

Moreover, ASRS 150 preferably is configured to control press system 110to cause press system 110 to create the types of pellets that ASRS 150has determined are in highest demand. ASRS may thus, order pellets in apuck, and then store those pucks for piecing together a kit with thecorrect number of pellets of the correct type. Moreover, in an exemplaryembodiment, ASRS 150 is configured to facilitate ordering materials usedto create the pellets.

Although described herein as a storage and retrieval system, whereinpellets are created and stored in lots, and retrieved when called uponfor construction of thermal batteries, in other embodiments, theautomated storage and retrieval system is configured to cause pellets tobe created on demand and delivered to the automatic stacker directly. Infurther exemplary embodiments, the automated storage and retrievalsystem not only requests and/or confirms the delivery of material to thedesignated points in the process, but it may control the delivery of theparts.

In accordance with an aspect of an exemplary embodiment of the presentinvention, ASRS 150 is configured to automatically request the thermalbattery components from storage. Stated another way, ASRS 150 isconfigured to automatically request pucks that hold the specific pellettypes. ASRS 150 is preferably configured to deliver those pucks to thestacker in an automated manner. However, some or all of the products maybe moved manually.

In another exemplary embodiment, the ASRS is configured to receiveinformation identifying desired features or qualities of a thermalbattery. For example, a user may input a thermal battery model numberinto the ASRS system. The ASRS preferably is configured to process suchinformation and create instructions for making such a battery. Theinstructions may, for example, be delivered to operators in any suitableformat, e.g., printed, digitally, and/or the like.

Also, the ASRS preferably is configured to provide instructions to theautomatic stacking, wrapping, and testing systems to facilitate thepackaging of the components. Moreover, the ASRS system preferably isconfigured to control one or more of these systems without humanintervention or with minimal human intervention.

In accordance with one aspect of an exemplary embodiment of the presentinvention, ASRS 150 comprises a computer, a database, a puck storagelocation, and/or a device for recognizing the identity of the carriers,for example, ASRS may comprise a bar code scanner. However, otherelectronic devices may be used to receive and process tracking data suchas the serial number and other information. ASRS 150 also preferablycomprises robotic product movers, conveyor belts, and/or the like.However, other devices may be used for moving carriers of products fromone location to another and for selectively routing those carriers.

In accordance with another aspect of an exemplary embodiment of thepresent invention, ASRS 150 is configured to receive data from varioussystems and/or devices in thermal battery manufacturing system 100. Thisdata preferably is related to the unique identifier and preferably isstored in a database associated with ASRS 150. The data preferably isreceived from press system 110, from various quality control systems,from stacker 120, and from wrapper 130.

Preferably, the unique identifier identifies a particular puckcontaining pellets of a particular type. Thus, the data may specify thecontents of the puck, the number and type of pellets in the puck, theaverage weight, density, and/or thickness of the pellets, informationregarding the composition of the pellets, the materials from which thepellets in that puck were made, the environmental conditions at the timeof manufacture of those pellets, the number of pellets discarded from aparticular run of pellets, the individual weights, thicknesses, and/ordensities of the pellets, and/or the like. Furthermore, ASRS 150 isconfigured to track the movement of the puck from one location toanother based on the unique identifier.

In one exemplary embodiment, the data tracking, inventory, materialretrieval and storage, and data analysis preferably is facilitated usingan electronic data package such as a PLEXUS data package. However, otherdata packages and inventory management software may also be used totrack inventory and associated data.

In accordance with an aspect of an exemplary embodiment of the presentinvention, method 200 is configured to track components, subcomponents,end products and/or “properties” of those products. Tracking may, forexample, involve the steps of automatically storing and retrievingcomponents, subcomponents and/or end products and associated data (step250).

In accordance with one aspect of an exemplary embodiment of the presentinvention, a method 600 for improving the reject rate of thermalbatteries may comprise the steps of associating a unique identifier witha group of pellets (step 610), tracking the group of pellets (step 620),creating kits (comprising groups of pellets) based on the uniqueidentifier (step 630), and delivering the kits to a stacker thatassembles a thermal battery from the kits (steps 640 and 650). Themethod may further include the step of recording information associatedwith the group of pellets.

The group of pellets may, for example, all share a commoncharacteristic. For example, the pellets may all be anode pellets, theanode pellets may all be in the heavy category, and/or the like. Some ofthese pellets may be grouped in a puck. In one embodiment, the step ofassociating a unique identifier with a puck (step 610) may include thestep of labeling a puck with a bar code.

Furthermore, the step of creating a kit (step 630) comprises the stepsof selecting from among a plurality of pucks two or more pucks to form akit. The kit may, for example, contain an anode puck, a cathode puck, anelectrolyte puck, and a pyrotechnic puck. In accordance with one aspectof an exemplary embodiment of the present invention, the number of pucksand the type of material in each selected puck is based on a recipe formaking a particular thermal battery. Thus, the step of creating a kitfurther includes the step of selecting a puck for a particular recipebased on the number of pellets in each puck and/or materialcharacteristics of the pellets in that puck. The kit preferablycomprises some or all of the pellet components that are used to build anidentified thermal battery.

In accordance with one aspect of an exemplary embodiment of theinvention, the kitting system is configured to facilitate automaticdelivery of battery construction materials to the stackers, for exampleby assembling a “kit” of pucks. The kitting system (or kitting“station”) may be configured to communicate with both the stackers andthe ASRS. The stacker, in accordance with one exemplary embodiment, isconfigured to request one or more kits of the kitting station. Forexample, when a stacker has completed the assembly of a battery stack itrequests that another kit of pucks be delivered. In one exemplaryembodiment, the kitting station receives this request from the stackerand communicates a request to the ASRS to provide pucks containingspecific types of pellets for the specific battery or batteries thatwill be assembled by the stacker.

The ASRS is configured to provide requested pucks to the kitting system.In one exemplary embodiment, the pucks that are included in the kit areselected to provide the types of pellets used to produce a single typeof battery. In one exemplary embodiment, the ASRS is configured toautomatically transport pucks to the kitting station via a conveyorsystem. In another exemplary embodiment, the kitting station assemblesthe pucks onto a pallet and releases the pallet to be delivered to thestacking station, where the stacking station unloads the pucks from thepallet.

The kitting station may also facilitate return from the stacker of aused pallet of pucks. In one exemplary embodiment, the kitting stationis configured to receive a pallet from the stacker and automaticallyremove empty or partially empty pucks from the pallet for reuse. Thepallet is then available for the next kit to be assembled. The kitingstation may be configured to use a pneumatic or electronically actuatedmechanical gripper. The kitting station is configured to read the uniqueidentifier on each puck, for example, with a bar code scanner, toidentify the puck and/or its contents. Identification of the puck and/orits contents facilitates loading and/or unloading specific pucks andplacement of specific pucks in desired locations on or off of thepallet.

Thus, ASRS 150 is preferably configured to automatically assemble thekit based on input identifying the particular thermal battery to bebuilt and/or to deliver the kit to an assembly station.

The invention may be described herein in terms of functional blockcomponents, optional selections and/or various processing steps. Itshould be appreciated that such functional blocks may be realized by anynumber of hardware and/or software components suitably configured toperform the specified functions. For example, the invention may employvarious integrated circuit components, e.g., memory elements, processingelements, logic elements, look-up tables, and/or the like, which maycarry out a variety of functions under the control of one or moremicroprocessors or other control devices. Similarly, the softwareelements of the invention may be implemented with any programming orscripting language such as C, C++, Java, COBOL, assembler, PERL, VisualBasic, SQL Stored Procedures, extensible markup language (XML), with thevarious algorithms being implemented with any combination of datastructures, objects, processes, routines or other programming elements.Further, it should be noted that the invention may employ any number ofconventional techniques for data transmission, messaging, dataprocessing, network control, and/or the like.

It should be appreciated that the particular implementations shown anddescribed herein are illustrative of the invention and its best mode andare not intended to otherwise limit the scope of the invention in anyway. Indeed, for the sake of brevity, conventional data networking,application development and other functional aspects of the systems (andcomponents of the individual operating components of the systems) maynot be described in detail herein. It should be noted that manyalternative or additional functional relationships or physicalconnections might be present in a practical thermal batterymanufacturing system.

As may be appreciated by one of ordinary skill in the art, the inventionmay take the form of an entirely software embodiment, an entirelyhardware embodiment, or an embodiment combining aspects of both softwareand hardware or other physical devices. Furthermore, the invention maytake the form of a computer program product on a computer-readablestorage medium having computer-readable program code means embodied inthe storage medium. Any suitable computer-readable storage medium may beutilized, including hard disks, CD-ROM, optical storage devices,magnetic storage devices, and/or the like.

These computer program instructions may also be stored in acomputer-readable memory that may direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement functions of flowchart block or blocks. The computerprogram instructions may also be loaded onto a computer or otherprogrammable data processing apparatus to cause a series of operationalsteps to be performed on the computer or other programmable apparatus toproduce a computer-implemented process such that the instructions whichexecute on the computer or other programmable apparatus include stepsfor implementing the functions specified in the flowchart block orblocks.

In the foregoing specification, the invention has been described withreference to specific embodiments. However, it may be appreciated thatvarious modifications and changes may be made without departing from thescope of the invention. The specification and figures are to be regardedin an illustrative manner, rather than a restrictive one, and all suchmodifications are intended to be included within the scope of invention.Accordingly, the scope of the invention should be determined by theappended claims and their legal equivalents, rather than by the examplesgiven above. For example, the steps recited in any of the method orprocess claims may be executed in any order and are not limited to theorder presented.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as critical, required, or essentialfeatures or elements of any or all the claims. As used herein, the terms“comprises”, “comprising”, or any other variation thereof, are intendedto cover a non-exclusive inclusion, such that a process, method,article, or apparatus that comprises a list of elements does not includeonly those elements but may include other elements not expressly listedor inherent to such process, method, article, or apparatus. Further, noelement described herein is required for the practice of the inventionunless expressly described as “essential” or “critical”.

1. A system to produce a thermal battery, comprising: a press systemcomprising a rail and shoe system to form pellets from a powdermaterial; a stacking system associated with the press system, thestacking system configured to select pellets from a plurality of storagecontainers and to stack the selected pellets in a predetermined ordervia a positive air pressure pellet carrier device; and an enclosingsystem associated with the stacking system, wherein the enclosing systemis configured to hermetically enclose the stacked pellets, and whereinat least one of the press system, the stacking system, and the enclosingsystem is substantially automated.
 2. The system of claim 1, wherein thepress system comprises a servo press.
 3. The system of claim 1, whereinthe powder material comprises: one of a lithium/aluminum compound and alithium/silicon compound suitable for forming an anode pellet.
 4. Thesystem of claim 1, wherein the powder material comprises: an irondisulfide or cobalt disulfide compound suitable for forming a cathodepellet.
 5. The system of claim 1, wherein the storage container is apuck and wherein the press system is configured to sort pellets intomore than two pucks such that each puck comprises pellets ofsubstantially the same material and pellets that substantially share atleast one of the following characteristics: weight, density, andthickness.
 6. The system of claim 1, wherein the stacking system isconfigured to select appropriate pellets for forming a thermal battery,and to stack the selected pellets on a stacking fixture; wherein thepellets are selected based on at least one of weight, thickness,material, and density of the selected pellet.
 7. The system of claim 1,wherein the stacking system is configured to select and stack in apre-determined order a plurality of pellets, wherein at least twopellets of the plurality of pellets comprise substantially differentmaterials.
 8. The system of claim 1, wherein the enclosing system isconfigured to weld a seam between a thermal battery container and athermal battery cap when pressed together, the enclosing system furthercomprising a laser and a weld torch; wherein the weld torch isconfigured to seal the puck base to the puck cap in an automated manner,wherein the laser is configured to facilitate adjusting the position ofthe weld torch to maintain a constant distance between the weld torchand the seam.
 9. The system of claim 1, further comprising: an inventorysystem coupled to at least one of the press system, the stacker system,and the enclosing system to at least one of track, store, and retrievethe pellets while the pellets are located in at least one of the presssystem, the stacker system, and the enclosing system.
 10. The system ofclaim 1, wherein at least one of the press system and the stackingsystem comprises a positive air pressure pellet carrier deviceconfigured to utilize the Bernoulli principle to lift a selected pellet.11. The system of claim 10, wherein the positive air pressure pelletcarrier device further comprises an air knife configured to remove oneor more non-selected pellets that have been lifted by the positive airpressure pellet carrier device.